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.\" Common Development and Distribution License ("CDDL"), version 1.0.
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.\" 1.0 of the CDDL.
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.\" Copyright 2015 Joyent, Inc.
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.Dd May 11, 2016
.Dt PSETBKPT 3PROC
.Os
.Sh NAME
.Nm Psetbkpt
.Nd set a breakpoint trap in a process
.Sh LIBRARY
.Lb libproc
.Sh SYNOPSIS
.In libproc.h
.Ft int
.Fo Psetbkpt
.Fa "struct ps_prochandle *P"
.Fa "uintptr_t address"
.Fa "ulong_t *saved"
.Fc
.Sh DESCRIPTION
The
.Fn Psetbkpt
function sets a breakpoint instruction at the address
.Fa address
in the process handle
.Fa P .
The instruction that used to be set will be set in
.Fa saved
and should be retained.
.Pp
A breakpoint will remain in place until a subsequent call to
.Xr Pdelbkpt 3PROC .
The value stored in
.Fa saved
should be passed as the third argument to
.Xr Pdelbkpt 3PROC .
.Pp
When a process executes an instruction that has been replaced with a
breakpoint it generates a
.Sy FLTBPT
trap
causing the thread to stop.
.Pp
Note, breakpoints may only be set in active processes.
They may not be set in process handles that refer to core files, zombie
processes, or files.
.Sh RETURN VALUES
Upon successful completion, the
.Fn Psetbkpt
function sets the breakpoint and
returns
.Sy 0 .
Otherwise,
.Sy -1
is returned and
.Sy errno
is set to indicate the error.
.Sh ERRORS
For a full list of possible errors see the
.Sy DIAGNOSTICS
section in
.Xr proc 5 .
.Pp
The
.Fn Psetbkpt
function will fail if:
.Bl -tag -width Er
.It Er ENOENT
.Fa P
does not refer to an active process.
.It Er EBUSY
A breakpoint instruction was already written by another debugger.
.El
.Sh INTERFACE STABILITY
.Sy Uncommitted
.Sh MT-LEVEL
See
.Sy LOCKING
in
.Xr libproc 3LIB .
.Sh SEE ALSO
.Xr libproc 3LIB ,
.Xr Pdelbkpt 3PROC ,
.Xr proc 5
